Answer: 0.0328 A
Explanation:
Given
No of turns [tex]N=920[/tex]
Length of solenoid [tex]L=0.380\ m[/tex]
Magnetic field [tex]B=10^{-4}\ T[/tex]
the magnetic field at the center of the solenoid is
[tex]\Rightarrow B=\mu nI=\mu \dfrac{N}{L}I[/tex]
Putting values we get
[tex]\Rightarrow 10^{-4}=4\pi \times 10^{-7}\times \dfrac{920}{0.380}\times I\\\\\Rightarrow I=\dfrac{0.380\times 1000}{920\times 4\pi}=0.0328\ A[/tex]